End Stage Renal Disease (ESRD) is a devastating chronic illness which affects nearly 200,000 patients each year in the United States. The average annual per-patient cost of treatment is nearly $30,000, nine to ten times that of an average individual. The aggregate cost of ESRD care, $7 billion, is growing rapidly due to increasing enrollment of patients age 65 and older. Despite the benefits of kidney transplantation, a limited pool of donors and comorbid disease obligates most ESRD patients to chronic dialysis. This care is performed on an ambulatory basis. Choices of dialysis prescription, modality and dose, by physicians and patients are fundamental to the care of ESRD patients, vary considerably in the U.S. and could have enormous cost implications given the large per-patient costs. The choice of therapy in routine practice should reflect a comprehensive understanding of outcomes and costs of alternative prescriptions, and of the tradeoffs which they entail. However, neither the outcomes, the costs nor the tradeoffs are characterized well. We have formed a multidisciplinary team to investigate factors that influence the choice of a particular dialysis prescription, to assess patient outcomes and costs of alternative dialysis prescriptions in the United States, and to formulate optimal dialysis strategies that take into account the perspectives of patients, providers and payers. Our research will include: 1) a national prospective cohort study of mortality, morbidity, symptoms, quality of life, patient satisfaction and costs associated with alternative dialysis prescriptions; 2) a cross- sectional and follow-up study of patient preferences for alternative prescriptions; 3) a cross-sectional survey of nephrologists and dialysis facility administrators to ascertain factors affecting the choice of therapy; 4) a study of the impact of resource utilization in outpatient dialysis on mortality, morbidity and overall costs for all facilities and facilities of different organizational types; and 5) an analysis of the cost-effectiveness of alternative prescriptions. This research will provide information that can be used by physicians and policymakers to guide and improve dialysis management in the United States.